Climate-space models were constructed for 241 plant species from a sample of 86 nature reserve communities in Great Britain. Convex Hull climate envelopes were used to compile Mutual Climatic Range diagrams for selected species at each site. Present-day and potential future climatic values over the next 100 years were compared against the climatic ranges of the species. A new Combined Envelope (a quadratic logistic regression probability surface constrained by a Convex Hull envelope) was used in a Climate Change Trend Analysis to determine future climatic suitability for species at each site (defined as a change in probability of species' presence). Results indicate that the warming climate could favour a large proportion of plants on Scottish reserves (excepting montane species) and be less favourable for many plants on reserves in the south of England. The situation appears to be one of 'no change' for the majority of species on Welsh reserves and those further north in England.